Stereocampimeter



June 23, 1925. 1,543,188

MQ POSER STEREOCAMPIMETER Filed Jan. 5, 1921 4 Sheets-Sheet 2 &

:IEIEiEIE l l 4 .V I

June 23, 1925. 1,543,188

' M. POSER STEREOCAMPIIIETER Filed Jan. 5; 1921 4 Speets-Sheet 5 J H a 1 e 1 e i 1 I 6' I E W 4 H 1:

INVENTOR..

mj aser ATORNEY.

PatentedJnne 23, 1925. i

UNITED STATES PATENT OFFICE. A

MAX POSER, OF ROCHESTER, NEW YORK, ASSIGNOR T0 BAUsCH' & LOMB OPTICAL COMPANY, or ROCHESTER, NEW YORK, A CORPORATION on NEW YORK.

STER OCAMPIMETER.

Application filed January 3, 1921. Serial No. 434,492

To all whom it may concern: I

Be it known that LMAX PosER, a Citizen of'the United States, residing at Rochester, county of Monroe, and State of New York, have invented certain new and useful Improvements in Stereocampimeters; and I do hereby declare the following to be a full, clear, and exact description of the same,

reference being had to the accompanyingv drawings, forming a part of the specification, and to the reference numerals marked thereon.

The presentinvention relates to optical instruments, more especially to those used for the determination or outline of central or paracental scotomata, that is, blind areas on the retina of the eye, which may be blind only for certain colors and located in a portion of the retina coming within the field of the instrument, or it may include areas which are totally blind. The object of my invention is to provide a device of the above class in which the selection and arrangement of lenses may enable an accurate and precise outline to be determined of the various scotomata, which shall be effective throughout a wide angle or large field andwhich may possess the advantages accruing from binocular fixation of the visual axes as in a stereoscope. To these and other ends the invention consists in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features .being pointed out in the claims at the end of the specification.

In the drawings: Figure l is a side or end view of mylimproved-campimeter in a'preferred form.

Figure 2 is a section on the line 2' a of 'Figure 7, showing the'lenses decentered'to the observers eyes.

- Figure 3 shows a top plan view of the device shown in Figure 1.

Figure 4 is a section on the line l -.4 of

Fi ure' 3.

igure=5 represents a preferred form of chart for degrees.

use with my devlce, graduated into scribing Figure 6 shows a rear view of the stage 18 with the removable campimeter slate havmg the chart shown in Figure 5 On the reverse side.

Figure 7 is a front view of the device shown in Figure 1.

Figure 8 shows one of the markers or test objects having colored ends.

Figure 9 is an enlarged view on the line 9 9 of Figure 8.

Figure 10 represents a modified form of my device in which the fixation points are more widely separated to increase the nasal angle and in which the chart is curved.

Similar reference numerals throughout the several views indicate the same parts.

A campimeter literally signifies a device for determining or measuring the field of vision, but the present instrument is one for measuring or outlining such fields or areas on the retina of large angular extent with binocular fixation. The instrument operates on the principle of a stereoscope in which both eyes are focused on similar test figuresor charts which, when the lines of sight or visual axes are in correct alinement appear as a single image in which case there is said to be fusion. The centers Of .the

test figures or charts on which the eyesare eyes Open and focused so that the one not under examination helps the eye under inspection to remam 1n aconstant position on the fixation point since a patient cannot move one eye independently of the other.

An. accurate outllneof an important area like the optical center, or the blind spot area for example, is of greatvalue to the ophthalmologist or physician in diagnosis, and the more certain the Outline, the greater reliance may be placed on the s m toms when pretreatment, an -t e better is the practitioner enabled to. recognize symptoms of incipient eye troubles. The determination of scotomata to different colorswill indicate to. the experienced ophthalmologist or physician the pathological condition and osetc. In, addition to the use of colored objects-white'isnecessar to distinguish between blind areas on t e retina from those having slightly better power of vision.

Referring to the drawings the numeral 10 indicates a supportingbase suflici-ently wide-spread to afford a'rigid or firm-foundation for the instrument when" located on a table or similar support and provided on the bottom with pads 11 of rubber' or other yieldable material to 'prevent scratching a polished surface. The supporting column 12 is telescopically extensible to elevate the instrument, which may be retained at difi'er- 3d The. frame 15 comprises a head piece 16 in which are located a plurality of lenses 23 and 24, a dividing wall 17 for always saparating the two lines of sight, and an object stage 18 which is adapted to carry either paper charts or the campimeter slate 31.

In the embodiment shown, thestage 18 is adjustably mounted on a pair of rearwardly extending arms 19 fixedto the mainframe 15, and at least one of which is preferably graduated to-indicate the distance from the lenses 24 while one or more clamping screws 20 may secure the stage in the position de':

record 'chart,'and the markings on the slate on any blackboard. 'The'charts or slates sired. For convenience in orienting or properly positioning test charts on the .stage 18, the sides thereof may be graduated as shown at 21 and a pair of clamping bars 22 may be vertically slidable to retain thereon charts of different size. Any form'ofstereocampimeter chart maybe used and if transmitted light is required for transparent charts,the stage may be made of translucent material in order that the chart may be illuminated. Instead of using a slate 31 or blackboard, paper charts may be placed on the stage, or transparent test-charts may be placed in operative position, shown in Figure 6.. The campimeter slate bein preferably graduated into degrees in all irections' from each fixation point as shown in Fi ure 7 5," enables the operator to determine de ects on the'retina in definite location and measurementisuch records of defects or lesions may then be easily copied on a permanent.

may then bewiped off like the chalk marksinstrument is. therefore .inde

varies as the tangent of the angle as shown by Figure or the chart may be hollow spherical in shape as shown in Figure 10 B sibly the nature or the cause of the'les1on, when the graduations will be ofequal value or extent, and therefore easier to lay 'out. Obviously a chart may if desired, be arcuate shaped in only one direction as foi' example laterally or if it is desired to make the graduations equal in all directions, that-is both vertically and horizontally, the surface of the chart may be spherical or arcuate, both vertically and horizontally.

Located in the head piece 16 are a plurality of meniscus lenses 23 which are superiorly corrected to practically eliminate astigmatism of oblique pencils of rays over an area; of 30 degrees from the center of the field, that is such lenses are corrected so that bundles of central or oblique rays up to an angle of 60 degrees are united in the same plane provided that only a portion of the lens is used at a time, as is; the case when the human eye is looking through a spectacle lens, i. e. the: area of the lens determined by the size of the pupil of the human eye with the vertex of the lens approximately 12 to 13 millimeters from the apex of the cornea From Figure 2 of the drawings it will be seen that these lenses 23 function as prisms of a stereoscope, since in the embodiment shown the lenses 23 are thicker in the cen outer or peripheral part thereof, and the observers eyes are placed in a horizontal plane, eccentric, andtowards the nose from rel portion. than in thethe lens center. This lens 23 may constructed in other ways in order that it may a still function as a prism, for example byhaving the centers of'curvature of its two faces decentered to make the lens thicker on one side than on the other. lenses 23 decentered in a horizontal plane nasalwards with respect to the observers eyes inthe manner indicated. and the campimeter. slate at the focal plane of'the lenses, it will be apparent that'no adjustment, need normally fbe made for variations in the distance between the observers eyes, and this ndent of the interpupillary distance. Wi t some patients no additional prism is necessa fusion, but with others it hasv en found that the introduction of'additional prisms-24 adjacent the lenses 23 aifords'a convenient means of facilitating fusion. With eyes in which hyperphoria is present, that'is in which the visual axes are in different planes formin -a vertical angle, this ma be corrected byrotating either or hot of the Prime 24 by means of the milled head-25. The amount of such rotation is. indicated by the scales 26 in which each. graduation in the embodiment shown has a value of one-half prism-diopter. Adjacent the prisms to attain.

24 are located stationary containers 27 for additional prisms 32 of different strengths which may be inserted, if necessary, to establish proper fusion. When using the stero-campimeter the patients vision should be previously corrected for distance. For

-s ecial tests itmay sometimes be desirable ocmoveeither or both of the lenses 23 laterally in which event adjusting screws with milled heads 28 are provided and scales 29 to indicate the lateral separation of the centers of the lenses 23. Since many of the existing charts for scotomata test are for use on a stage at a distance of a hundred and ninety millimeters from the lenses, the focal length of the optical system of the stereo-campimeter has been chosen for that 'power, but it is not confined to that focal length. It may be necessary to move the stage on the rearwardly extending arms 19,

to attain a clear focus of the imagewhen the patient has not been fully corrected for distance vision. With ordinary artificial illuminants or even daylight at various times of the year, colors of the test objects may change rendering the test inaccurate, and for this reason it is more advisable to use a standard form of daylight lamp with the present stereo -campimeter in order to insure a constantcolor composition. The -determination of the blind areas on the retina is made after careful fixation of the patients eyes has been accomplished, by

moving test objects 33 of different sizes and colors across the field from center to margin and vice versa, in various di- I rubbing off.

In the modification shown in Figure'lO, the use of one or more reflectors 35,- which may bemirrors or prisms disposed as indicated enable each field to be increased a considerable amount in the nasal angle or on the side of the fixation point remote from the blind spot. The curved form (hollow spherical) of .chart ll8 is also adapted for use in other forms of the device.

In operation, the stage is adjusted to that inclination which will give the best illumina tion and which is most convenient for the operators use. After having corrected the patient for distance vision, fusion should be obtained in the manner previously stated by rotation of the prism 24 or the addition" of prisms 32 to the holders 27 if necessary. A J aval chart 30 or Wells chart may be used in testing for proper fusion. With the patientseyes constantly focused on the fixation points, each eye ma be tested separately by moving one o the test objects across its field and back and having the patient indicate when the same is out of his view 'or when he can :no longe1- 'distin ish itscolor. A chalk mark may be ma e on the slate at each point where the test object. either disappears or chan es its color. By a; series of such movement ofthe test object curves may be obtained indicating the outline of someparticular scotoma. Inasmuch as the chartsused are preferably graduated in degrees on all sides of the fixation point, the location of anyfarea relative to the fovea centralis or relative to the normal blind spot may be accurately determined. In "the presenttype of stereo-campimeter employing binocular fixation. the eye not under test aids the one under examination in its endeavor to remain focused on the fixation point. It will be apparent that in the case of strabismus, or those in which it is not possible to correct fusion, each eye may be tested separately, and the device used as a monocular instrument by covering up the other eye, lens or chart.-

Among the advantages of the present invention it should be stated that the use of a lens 23 of the type described enables the field of operation to be greatly extended and the outline of blind areas to be determined consistently with great accuracy. Were some type of lens 23 used other than the meniscus form described, such a lens would probably only givecorrect readingsup to about 15 degrees from the fixation point, while with the use of a lens of the type described oblique rays of a wide angle from theoenter of the field are superiorly corrected to practically eliminate astigmatism and since the normal blind spot-is located within prism 24 or'the use of additional prisms 1n 12 the holders 27 is especially worthy of notice. The various adjustments described for my improved stereo-campimeter enable the same to be used at any angle desired or found most con enient and adaptthe instrument for use with all forms of charts. As.

used in the claims, the term colored includes black and white as well as colors.

- I claim as my invention:

.1. stereoscope having for each eye a meniscus lens corrected to practically climinate astigmatism of oblique pen ils over an grees area of thirty degrees from the center of the field, the centers of said lenses being laterally separated more than the interpupillar-y distance of the observers eyes.

2. A stereo-campimeter employin binocu-- lar fixation havin for each eye a ens corrected to practica y eliminate astigmatism in obli ue pencils over an area of thirty deom the center of;tl1e field, and a.

prism juxtaposed to each lens between the 4 latter andthe object to be observed.

I 3. A stereoscope having a positive meniscus lens decentered in a horizontal plane with respect to the observers eye .to oper- ',ate as a prism and'mounted for lateral adjustment .upon the-stereoscope.

4. A stereoscope having at least one lens corrected to practically eliminate astigmatism ofoblique rays over an area of thirty degrees from the center of the field and a frotatable prism juxtaposed to said lens.

5. A stereoscope having a lens corrected to practically eliminate astigmatism of oblique rays over an area of thirty degrees;

from the center of-the field and a holder for removably supporting a prism in operation with said lens. f 6. The combination with a stereoscope of prismatic means. for the attainment offusion when the visual axes are out 'of'=-alinement any direction and means'for' adjusting said prismatic means.

7. A stereo-camplmeter having at least one meniscus lens corrected in, such mannor that central pencils of rays or oblique pencils'o'f rays upto an angle of sixty degreesare united in the same plane provided that only d'portionof the lensis used at a The combination with astereo-camph meter having a graduated slate provided with'a wide angle :field including the normal 'blind spot, of a firm supporting base therefor and means {or adjusting said to difierent heights and "to difam angles ofinclination. v j 9. A stereo-campimeter comprisin j' in combination lenses correctedto practically eliminate astigmatismot oblique rays over optical co I ment with the. optical center. I I 1 MAXPQSER.

an area of thirty degrees from the center'- of the field, rotarily' ad'ustable prisms adjacent said lenses, hol ers for removable prisms of difl'erent, powersin optical cooperation with the'first mentioned prisms and lenses, the centers of said lenses being adjustably se arated laterally more than I the interpupil ary distance ofthe observers eyes, a stage having a field-including the normal blind spot area/and adjustable to and from the observers eyes, as well as to different angles of inclination, a rigid supporting base and means for adjusting the height of said-campimeter above the base. 10. A stereoscope having a meniscus lens adjustably mounted to operate as a prism corrected to practically e i'minate astigmatism of oblique rays over an area of thirty degrees from the center of the field, a .rotatableprism juxtaposed to said lens, and

v a container for a removable prism inoptical cooperation with said lens and rotatable prism.

arcuate shaped in at least one direction.-

- -13.-A stereo-campimeter having at least one reflector in a. line of vision for-enlargement of the field on the nasal or opposlte side of the fixation point from the normal blind spot.

12. A stereo-campimeter having a chart 14. In a stereo-campnneter, the combination with a chart having a graduated surface curved in at least one direction to an arc of a circle, of a lens for use with said chart, said lens being corrected to practi cally eliminate-astigmatism of oblique rays I over an angle, of thirty center of the field. I

15. A. stereoscope provided with a menisdegrees from the one lens having its geometric center nor-.

mally displaced horizontally with-respect to theobservers eye and laterally adjustable.

. 16. A stereoscope provided with a eta having thereon marks vto aid in correct y locating an object heldjthereby, and having at least'one vslidable clamping bar cooperating with said marks toretain objects ofdifl'erent size in position in align- 

